Hello,
You can force all loaded tiles to use higher detail by decreasing the Maximum Screen Space Error parameter in the Level of Detail settings on a 3D Tileset. However, this is not recommended for the purposes of converting tilesets to static meshes. Geospatial and photogrammetry data can get huge very quickly, and you’re likely to encounter significant performance problems when trying to use tilesets as a static mesh - especially when the tiles use a high level of detail.
While we don’t currently support it, we are exploring the possibility of downloading tiles to use offline for situations like this. You can view previous discussion on the topic here.